The overall objective of the proposed research is the study of the regulation of cellular immune responses both clinically and in the experimental laboratory with the goal of applying the information obtained to problems of clinical organ transplantation and of immunity to solid tissue tumors. Particular emphasis will be placed on the investigation of the immunosuppressive properties of an immunoregulatory alphaglobulin (IRA) extracted from normal human serum. Clinical studies will also include an evaluation of cellular immune responses in patients with cadaver kidney transplants receiving conventional immunosuppressive therapy and rabbit antihuman thymocyte globulin (ALG). Laboratory studies include the development of a specific immunoassay for IRA for future clinical application and the use of IRA alone or in combination with ALG in attempts to induce immunological tolerance to tissue allografts in experimental animals. Moreover, we will apply the RNA- mediated transfer of cellular immunity in studies designed to transfer tumor specific immunity in inbred mice and will continue a study of the biochemical mechanisms involved in this transfer system.